I've wondered the same. PIA's assistant airport director said that 60% of pax using BMI-DTW were from Peoria (metro area, I presume). After the service started, airport director Ken Spirito said some future flights were booked full. We may hear something soon - October is gonna be a busy month for us because 1 daily UAX PIA-DEN begins the 4th, G4 resumes twice-weekly PIA-PIE on the 6th and G4 starts twice-weekly PIA-IWA the 27th. SFB service and FLL starts in November and December, respectively. Additional destinations are said to be in the works.